Basis of Presentation and Summary of Significant Accounting Policies (Details) (USD $) In Millions, unless otherwise specified	1 Months Ended		12 Months Ended			11 Months Ended	12 Months Ended	11 Months Ended	12 Months Ended
	May 31, 2011	Jan. 21, 2011	Dec. 31, 2011 Y outlets plants refineries	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2011 Variable Interest Entity, Primary Beneficiary [Member]	Dec. 31, 2011 Variable Interest Entity, Primary Beneficiary [Member]	Dec. 31, 2011 Variable Interest Entity, Not Primary Beneficiary [Member]	Dec. 31, 2011 Variable Interest Entity, Not Primary Beneficiary [Member]
Basis of Presentation and Summary of Significant Accounting Policies (Textual)
Number of refineries owned by the company			16
Combined total throughput capacity of petroleum refining			3,000,000
Number of retail and wholesale branded outlets through which refined products are marketed			6,800
Number of ethanol plants owned by company			10
Combined capacity of ethanol (gallons per year)			1,100,000,000
Feed capacity of diesel plants		10,000
Estimated aggregate cost to construct diesel plant		$ 368
Joint venture ownership percentage							50.00%		50.00%
Payments to noncontrolling interests			22	0	0	22		22
Contribution of property						1		1
Variable interest entity, financial support, date of agreement	May 31, 2011
Variable interest entity, amount of financial support	$ 221
Variable interest entity, maximum percentage of construction costs financed	0.6
Maximum maturity period (in months) of temporary cash investments			3 months
Property, plant and equipment, minimum useful life			25
Property, plant and equipment, maximum useful life			30
Period (in years) of estimated undiscounted future costs resulted in environmental liabilities			20